/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.mahout.clustering.canopy;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;
import org.apache.mahout.matrix.Vector;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
public class CanopyMapper extends MapReduceBase implements
Mapper<WritableComparable<?>, Vector, Text, Vector> {
private final List<Canopy> canopies = new ArrayList<Canopy>();
private OutputCollector<Text, Vector> outputCollector;
@Override
public void map(WritableComparable<?> key, Vector point,
OutputCollector<Text, Vector> output, Reporter reporter) throws IOException {
outputCollector = output;
Canopy.addPointToCanopies(point, canopies);
}
@Override
public void configure(JobConf job) {
super.configure(job);
Canopy.configure(job);
}
@Override
public void close() throws IOException {
for (Canopy canopy : canopies) {
Vector centroid = canopy.computeCentroid();
outputCollector.collect(new Text("centroid"), centroid);
}
super.close();
}
}